基于视觉的智能脊柱畸形测量研究方法及临床初探

目的本研究旨在研制一款无需摄片即可了解脊柱形态的可视化智能方法。 方法采用"单摄像机、多视角"的系统构建方案以便后期应用于便携式设备。在原理验证实验中，利用相机测量一系列画在纸上然后贴在板上的标记物的三维坐标，验证该方法的可行性与精度。真实试验纳入了自2018年6月至2018年12月长海医院骨科就诊的11例患者，分析其临床特点、脊柱全长正侧位片以及基于该方法与Surgimap软件测量的冠状面Cobb角度数，对该方法的有效性进行评估。 结果原理验证实验中，认为利用五个图像计算Cobb角为最优策略，所得XOY和YOZ平面Cobb角的误差值基本控制在1°和2°之内，精度为1°。真实试验结果表明，本方法测量冠状面Cobb角具有可信度，但具体应用时仍需进一步优化。 结论该方法成本较低，便于普及与使用，无放射性危害，为今后家庭或社区式小儿脊柱形态监测，以及动态信息反馈提供客观依据，有广阔的应用前景。     

Use of the iPhone for Cobb angle measurement in scoliosis

Purpose

The Cobb technique is the universally accepted method for measuring the severity of spinal deformities. Traditionally, Cobb angles have been measured using protractor and pencil on hardcopy radiographic films. The new generation of mobile ‘smartphones’ make accurate angle measurement possible using an integrated accelerometer, providing a potentially useful clinical tool for assessing Cobb angles. The purpose of this study was to compare Cobb angle measurements performed using a smartphone and traditional protractor in a series of 20 adolescent idiopathic scoliosis patients.

Methods

Seven observers measured major Cobb angles on 20 pre-operative postero-anterior radiographs of Adolescent Idiopathic Scoliosis patients with both a standard protractor and using an Apple iPhone. Five of the observers repeated the measurements at least a week after the original measurements.

Results

The mean absolute difference between pairs of smartphone/protractor measurements was 2.1°, with a small (1°) bias toward lower Cobb angles with the iPhone. 95% confidence intervals for intra-observer variability were ±3.3° for the protractor and ±3.9° for the iPhone. 95% confidence intervals for inter-observer variability were ±8.3° for the iPhone and ±7.1° for the protractor. Both of these confidence intervals were within the range of previously published Cobb measurement studies.

Conclusions

We conclude that the iPhone is an equivalent Cobb measurement tool to the manual protractor, and measurement times are about 15% less. The widespread availability of inclinometer-equipped mobile phones and the ability to store measurements in later versions of the angle measurement software may make these new technologies attractive for clinical measurement applications.     

Relationship between gibbosity and Cobb angle during treatment of idiopathic scoliosis with the SpineCor brace

The objective of this study was to quantify the relationship between gibbosity and spinal deformation expressed by the angle of Cobb before and during treatment with a brace for different classes of idiopathic scoliosis patients. As part of the standard treatment with the Dynamic Corrective Brace (SpineCor), 89 idiopathic scoliosis patients underwent an initial radiological examination and gibbosity measurement with a scoliometer wearing and not wearing the brace. The 89 patients were classified in relation to the apex of the scoliosis curves: thoracic (n = 29); thoracolumbar (n = 40); lumbar (n = 7) and double (n = 13). With the dynamic corrective brace, the patients showed a mean decrease of 8.3° for the major Cobb angle, and a mean decrease of 2.3° for their gibbosity. There was a significant positive relationship between gibbosity and Cobb angle with and without the brace for the thoracic and thoracolumbar curves. A linear regression analysis identified a small mean estimation error for the thoracic curves (7.4° no-brace; 2.7° with brace) and thoracolumbar curves (5.2° no-brace; 5.3° with brace), indicating a predictive potential of the scoliometer. The measure of gibbosity with the scoliometer provides a fairly reliable estimation of Cobb angle at the initial clinical examination of a scoliosis patient. However, when initial Cobb angle and gibbosity are considered, the measure of gibbosity when wearing a brace provides the clinician with a highly reliable estimation of the Cobb angle while in a brace. This relationship also exists for the follow-up with a brace, permitting a judgement of the patient’s evolution under the treatment with SpineCor. Received: 23 September 1999 Revised: 9 March 2000 Accepted: 2 May 2000     

Assessment of two novel surgical positions for the reduction of scoliotic deformities: lateral leg displacement and hip torsion

Cobb angles and apical vertebral rotations (AVR) are two of the main scoliosis deformity parameters which spinal instrumentation and fusion techniques aim to reduce. Despite this importance, current surgical positioning techniques do not allow the reduction of these parameters. Two new surgical frame accessory prototypes have been developed: (1) a lateral leg displacer (LLD) allows lateral bending of a patient’s legs up to 75° in either direction and (2) a pelvic torsion device (PTD) which allows transverse plane twisting of a patient’s pelvis at 30° in either direction while raising the thoracic cushion, opposite to the raised side of the pelvis, by 5 cm. The objective of this study was to evaluate the ability of the LLD and PTD to reduce Cobb angles and AVR. Experimental testing was performed pre-operatively on 12 surgical scoliosis patients prone on an experimental surgical frame. Postero-anterior radiographs of their spines were taken in the neutral prone position on a surgical frame, and then again for 6 with their legs bent towards the convexity of their lowest structural curve, 4 with their pelvis raised on the convex side of their lowest structural curve and one each in opposite LLD and PTD intended use. Use of the LLD allowed for an average supplementary reduction of 16° (39%) for Cobb angle and 9° (33%) for AVR in the lowest structural curve. Use of the PTD allowed for an average supplementary reduction of 9° (19%) for Cobb angle and 17° (48%) for AVR in the lowest structural curve. Both devices were most efficient on thoraco-lumbar/lumbar curves. Opposite of intended use resulted in an increase in both Cobb angle and AVR. The LLD and PTD provide interesting novel methods to reduce Cobb angles and AVR through surgical positioning which can be used to facilitate instrumentation procedures by offering an improved intra-operative geometry of the spine.     

计算机辅助测量青少年特发性脊柱侧凸脊柱长度的方法及可行性分析

目的 :提出一种新的计算机辅助测量青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)脊柱长度的方法,评价其准确性和可重复性。方法:在前后站立位脊柱全长正位X线片上选取每个椎体的四个顶点,基于Matlab 6.5软件,设定程序确定L4下终板至T1上终板的中线,将中线上点的距离和作为脊柱长度。由1名医师采用计算机辅助测量方法和2名医师采用手工测量方法,随机选取5例AIS患者并对每例患者进行5次重复测量,计算两种方法测量结果的均值和标准差,评价计算机辅助测量脊柱长度方法的准确性和可重复性。选取45例AIS患者,其中女38例,男7例,年龄10～16岁(13.5±1.5岁);Cobb角10°～45°(32.5°±8.7°)。由同一骨科医师在前后站立位脊柱全长正位X线片上分别采用手工测量方法和计算机辅助测量方法获得T1～L4脊柱长度,计算均值和标准差,比较两种测量方法的结果是否存在差异。应用计算机辅助测量方法测量计算出45例AIS患者L4～T1的脊柱长度,对同一医师应用该测量方法间隔4周的两次测量结果做比较,分析同一观察者在不同时间的可重复性;对3名不同医师分别应用该测量方法的测量结果做比较,分析该方法不同观察者间的可重复性。结果:应用计算机辅助测量方法测量5例AIS患者的脊柱长度(±s)分别为325.8±0.46mm、391.3±0.43mm、476.7±0.04mm、441.3±0.79mm和432.8±0.50mm,2名医师应用手工测量方法测量5例AIS患者的脊柱长度分别为325.7±8.3mm、390.9±7.6mm、476.7±6.0mm、441.5±8.2mm、433.1±6.0mm和326.2±5.9mm、391.4±7.5mm、476.1±5.8mm、441.6±8.2mm、432.9±5.8mm,应用计算机辅助测量方法多次测量脊柱长度测得结果的标准差较手工测量结果低得多。采用计算机辅助测量方法与手工测量方法测量45例AIS患者的脊柱长度(±s)分别为404.7±43.2mm和405.1±45.5mm,两组均数比较差异无显著性(P0.05),采用计算机辅助测量方法测量AIS脊柱长度的同一观察者间隔4周的组内相关系数为0.995(P0.05),不同观察者间的组内相关系数为0.942(P0.05)。结论:计算机辅助测量AIS患者脊柱长度的方法较传统的手工测量方法操作简单,并且其准确性和可重复性均较好。     

Effect of frontal plane tibiofemoral angle on the stress and strain at the knee cartilage during the stance phase of gait

Subject‐specific three‐dimensional finite element models of the knee joint were created and used to study the effect of the frontal plane tibiofemoral angle on the stress and strain distribution in the knee cartilage during the stance phase of the gait cycle. Knee models of three subjects with different tibiofemoral angle and body weight were created based on magnetic resonance imaging of the knee. Loading and boundary conditions were determined from motion analysis and force platform data, in conjunction with the muscle‐force reduction method. During the stance phase of walking, all subjects exhibited a valgus–varus–valgus knee moment pattern with the maximum compressive load and varus knee moment occurring at approximately 25% of the stance phase of the gait cycle. Our results demonstrated that the subject with varus alignment had the largest stresses at the medial compartment of the knee compared to the subjects with normal alignment and valgus alignment, suggesting that this subject might be most susceptible to developing medial compartment osteoarthritis (OA). In addition, the magnitude of stress and strain on the lateral cartilage of the subject with valgus alignment were found to be larger compared to subjects with normal alignment and varus alignment, suggesting that this subject might be most susceptible to developing lateral compartment knee OA. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1539–1547, 2010     

青少年特发性脊柱侧凸柔韧性影响因素分析及仰卧侧屈角度的预测

目的分析青少年特发性脊柱侧凸柔韧性影响因素,探讨预测指标,初步建立仰卧侧屈位Cobb角角度的预测模型。方法通过对青少年特发性脊柱侧凸150例患者（包括胸椎侧凸和胸腰段/腰椎侧凸共216个）的站立位脊柱全长正位X线片和仰卧侧屈位X线片资料进行回顾性研究,用仰卧侧屈位X线片矫正率作为柔韧性指标,与站立位冠状面Cobb角、年龄、性别、Risser征、是否主侧凸和侧凸位置6个指标进行Pearson或Spearman相关分析及多元线性回归,筛选相关因素;采用同样方法 ,分析6个指标与仰卧侧屈Cobb角的关系。结果站立位冠状面Cobb角（P〈0.01）和侧凸位置（P〈0.01）与柔韧度存在明显线性回归关系。站立位冠状面Cobb角（P〈0.01）、侧凸位置（P〈0.01）和是否主侧凸（P〈0.01）与仰卧侧屈Cobb角存在明显的线性回归关系。对青少年特发性脊柱侧凸,站立位冠状面Cobb角每增加10°,柔韧度约减少8%,胸椎侧凸柔韧性平均比胸腰段/腰椎侧凸低10%。站立位冠状面Cobb角〉45°的胸椎次侧凸和〉50°的胸腰段/腰椎次侧凸,成为结构性侧凸几率较大。结论站立位冠状面Cobb角和侧凸位置是显著影响青少年特发性脊柱侧凸柔韧度的因素,实验探讨了1种预测仰卧侧屈Cobb角角度的简单方法 ,解决了临床实际问题。     

终板法与椎弓根法对青少年特发性胸椎脊柱侧凸Cobb角测量的比较

目的:对青少年特发性胸椎脊柱侧凸Cobb角测量的终板法和椎弓根法进行对比研究,比较两种方法的可信度、可重复性及两种方法测量结果的差异。方法:选取我院2010年7月～2011年3月门诊就诊的55例特发性胸椎脊柱侧凸患者,由一名高年资医师预先确定测量主弯的上、下端椎后,3名脊柱外科医师分别使用终板法和椎弓根法对站立位X线片进行手工测量评估,记录冠状面侧凸Cobb角数值,同时根据Nash-Moe法评估测量主弯上、下端椎的旋转度。1周后,打乱患者顺序,再由该3名医师重复测量。对测量结果进行可信度和可重复性分析,检验一致性并对两种方法的测量结果根据端椎旋转度和Cobb角大小分组进行分析比较。结果:终板法和椎弓根法测量主胸弯Cobb角的可信度和可重复性均为好～极佳的水平。终板法测量的总体可信度和可重复性分别为0.969和0.900,椎弓根法测量的总体可信度和可重复性分别为0.972和0.880。根据下端椎旋转度将AIS患者分组后的结果显示:下端椎无旋转组(Nash-Moe 0度)中椎弓根法与终板法测量结果无明显差异(P>0.05),而下端椎旋转明显组(Nash-MoeⅠ度和Ⅱ度)中椎弓根法测量结果较终板法小,差异有统计学意义(P<0.05)。根据Cobb角是否大于25°进行分组后的统计分析表明,在两组中椎弓根法测量结果均显著小于终板法(P<0.05)。结论:对于青少年特发性胸椎脊柱侧凸而言,终板法和椎弓根法测量Cobb角的可信度和可重复性均较好,但对于下端椎旋转明显(Nash-MoeⅠ度以上)的患者,椎弓根法较终板法测量结果小,建议对此类患者采用终板法测量Cobb角。     

Idiopathic scoliosis: relations between the Cobb angle and the dynamical strategies when sitting on a seesaw

The aim of this study was to determine the influence of the severity of the spinal curve on the postural regulation when self-imposed disturbances occur in a seated position in anteroposterior (AP) and mediolateral (ML) orientations. Twelve female adolescents with a right thoracic scoliosis (Cobb = 30.4° ± 9.7) were included in this study. The ground reaction forces (GRF) were studied while the subjects were maintaining their sitting on a seesaw (ML or AP destabilisation). Five conditions were tested: eyes open; with additional loads placed onto the subject’s right or left shoulder; or onto the subject’s right or left pelvis. We tested the correlation between the Cobb angle and the postural parameters (index of performance and GRF variability) for each condition. When the destabilisation was AP, the Cobb angle was significantly correlated with GRF variability and anterior and concavity index of performance. Two conditions showed higher correlations: stabilisation with the concavity pelvis load (GRF variability) and the open eyes (index of performance). In contrast, whatever the condition tested was, no link was found when the destabilisations were applied in ML direction. The destabilisation in a seated position highlights the influence of the curve severity on the postural organisation. In seated position, the postural control strategies specific to the scoliotic patients were always correlated by severity of curve, especially when the destabilisation is applied in AP directions. This study showed that the unstable seating position can be considered as a pertinent paradigm to help finding a postural clinical index for adolescent idiopathic scoliosis.     

Inter- and intraobserver reliability assessment of the Cobb angle: manual versus digital measurement tools

The objective of this study is to determine the intraobserver and interobserver reliability of end vertebra definition and Cobb angle measurement using printed and digital radiographs of 48 patients with scoliosis. The Cobb angle and the end vertebra were assessed by six observers in 48 patients with scoliosis using printed and digital radiographs. Definition of end vertebra and measurement of the Cobb angle was repeated three times with a 3 week interval. Intraclass correlation coefficients (ICC) were used to determine the interobserver and intraobserver reliabilities. 95% prediction limits for the errors in measurements are provided. For the Cobb angle a mean ICC of 0.97 was determined for intra- and interobserver reliability measurement of the printed radiographs. For the electronic radiographs a mean ICC value of 0.93 was determined for interobserver reliability and a mean ICC value of 0.96 for intraobserver reliability. Intraobserver ICC for definition of end vertebrae was 0.8 for both methods. Interobserver ICC was 0.83 for the manual and 0.74 in the digital method. One pitfall in angle measurement implies the Cobb method itself which measures in two dimensions. Until we develop a proper tri-dimensional measuring system an error is introduced. For the Cobb angle measurement the definition of end vertebrae introduces the main source of error. Digital radiography does not improve the measurement accuracy.     

用于测量Boston支具表面压力的无线压力传感器研制

背景：Boston支具广泛应用于青少年特发性脊柱侧凸（AIS）的矫形治疗,其力学设计仍待进一步改进。一些研究通过测量支具对躯体的作用力来探究支具的生物力学原理,但均为实验室测量结果,不能完全反映日常生活中支具对躯体的实际作用力。 目的：研制一种用于测量Boston支具表面压力的无线传感器。 方法：利用单点薄膜压力传感器及无线应变节点构建无线传感器,测量12例接受Boston支具治疗的AIS患者佩戴支具的表面压力以及相关的Cobb角改变。 结果：通过无线压力传感器测得支具上下压点垫片的压力以及臀部压力平均值分别为（5.11±0.66）N、（2.93±0.66）N和（0.86±0.17）N;佩戴支具后Cobb角由33°±13°减小至18°±13°,矫正了（49±27）%。 结论：所研制的无线压力传感器能够测量支具的表面压力,并为研制动态测量支具表面压力的设备提供了雏形。     

后路全脊椎切除术后脊柱畸形患者主弯各段Cobb角变化及其对主弯矫形的意义

目的:探讨后路全脊椎切除术(PVC)后脊柱畸形患者主弯各段Cobb角变化、对主弯矫形的意义及主弯置钉情况对矫形效果的影响。方法:对应用PVC治疗的46例严重僵硬性脊柱畸形患者进行回顾性分析。根据患者术前及术后所摄标准脊柱全长前后位X线片,在冠状面将畸形主弯划分为主弯上段、主弯中段及主弯下段。采用标准Cobb角测量方法分别对术前、术后主弯及主弯各分段Cobb角进行测量。比较主弯及主弯各分段Cobb角的变化、计算主弯各分段对主弯矫形的贡献率并进行统计学分析,同时观察主弯段椎弓根置钉情况及切除椎紧邻上下椎体的置钉情况与矫形率的关系。结果:患者术前主弯Cobb角平均为110.1°±18.1°,术后平均减小59.1°±16.4°(P<0.05),主弯矫形率为(54.1±12.2)%。其中,主弯中段平均减小28.1°±14.7°(P<0.05),对主弯矫形的贡献率为(49.1±27.3)%,主弯上段平均减小15.7°±13.1°(P<0.05),对主弯矫形贡献率为(25.2±16.6)%,主弯下段平均减小15.3°±12.4°(P<0.05),对主弯的矫形贡献率为(26.3±22.6)%。主弯上、下两段的矫形度数及矫形贡献率无统计学差异(P>0.05)。在切除椎的相邻的上下椎体至少各置入一枚椎弓根螺钉的患者有22例,该组患者主弯中段的矫形度要明显优于上、下椎体无钉的24例患者(P<0.05)。同时发现主弯节段置钉比率与主弯矫形率密切相关(r=0.82,P<0.05)。结论:主弯中段对主弯矫形的贡献率最大,主弯内椎弓根螺钉置钉数对矫形起重要作用,尤其在切除椎的邻近椎体置钉对脊柱矫形及重建更重要。     

强直性脊柱炎后凸截骨矫形角度的术前预测

目的评价强直性脊柱炎（AS）后凸畸形术前截骨角度预测方法的可行性。方法 2012-04-2013-12,依据选择标准对10例AS后凸畸形患者,术前采用脊柱股骨角预测方法进行术前截骨角度设计与预测。术前、术后2周及随访时摄脊柱全长正侧位X线片和大体像,测量全脊柱后凸角（GK）、胸腰椎交界角（TLJ）、腰椎前凸角（LL）、矢状面偏移（SVA）、骨盆入射角（PI）、骶骨倾斜角（SS）、骨盆倾斜角（PT）指标,VAS、ODI评分评估患者功能改善情况。结果 GK、TLJ、LL、SVA、SS、PT、VAS、ODI术后2周和末次随访时较术前明显改善,差异有统计学意义（P〈0.05）。PI术前、术后、末次随访时差异无统计学意义（P〉0.05）;各指标术后2周和末次随访时比较差异均无统计学意义（P〉0.05）。结论采用脊柱股骨角进行术前截骨角度设计对指导AS后凸畸形截骨矫形具有重要临床意义。     

The relationship between ankle dorsiflexion range of motion,frontal plane projection angle,and patellofemoral pain syndrome

BackgroundAnkle range of motion abnormalities have been often linked with alteration in knee kinematics leading to the development of patellofemoral pain syndrome (PFPS). Literature exploring the relationship between ankle dorsiflexion range of motion (DF ROM) and knee kinematics during functional tasks is scanty. This study aims to assess the relation between ankle DF ROM and frontal plane projection angle (FPPA), one of the knee kinematic variables, in individuals with and without PFPS during a step-down test.MethodsThis is a case-control study in which seventy PFPS patients and other 70 asymptomatic control subjects had their ankle DF ROM measured using an inclinometer with the knee flexed and extended. Their FPPA angles were measured using Kinovea software while doing the step-down test.ResultsWhen the two groups were compared, ankle DF ROM measured with the knee flexed was higher in the control group (33.15 ± 4.96) than in the PFPS group (30.20 ± 6.93) (p = 0.03). In both the PFPS group and the control group, the correlation between FPPA and ankle DF ROM with the knee flexed was statistically insignificant (p = 0.075 and 0.323 respectively).ConclusionDecreased ankle DF ROM can be one of the contributing factors to the development of PFPS in the context of greater dynamic knee valgus.     

Change in Cobb angle of each segment of the major curve after posterior vertebral column resection (PVCR): a preliminary discussion of correction mechanisms of PVCR

Introduction  

Posterior vertebral column resection (PVCR) is an effective technique for treating severe rigid spinal deformities, and no other osteotomy is capable for such an excellent corrective effects. The purpose of this study was to discuss the correction mechanisms of PVCR.     

髋臼后方包容角法和Keith法评价髋臼后壁骨折稳定性的对比研究

目的探讨髋臼后方包容角法评价髋臼后壁骨折髋臼后方稳定性的临床价值。方法选取30例单侧髋臼后壁骨折患者,在CT上分别采用髋臼后方包容角法和Keith法评估髋臼后方的稳定性,并对判定结果进行对比。结果髋臼后方的完全包容角、稳定包容角和不稳定包容角的平均值分别为92.38°±10.53°、73.86°±9.36°、51.90°±6.43°,2名测量人员自身和两者之间的组内相关系数(ICC)均0.95,说明此方法的可信度高且可重复性好。Keith法和髋臼后方包容角法对髋臼后方稳定性的判定结果具有高度一致性,Kappa值为0.824。以髋臼后方稳定性试验为参照,髋臼后方包容角法判定髋臼后方稳定性的特异性、敏感性和准确率均高于Keith法,但差异无统计学意义(χ2=0.834、0.764、0.904,P0.05)。结论髋臼后方包容角法与传统的Keith法在髋臼后壁骨折稳定性的判定结果基本一致,但该法不需参照对侧,操作简单,实用性强,尤其适用于对侧髋臼合并骨折或有先天性畸形的患者。     

骨关节炎患者股骨后髁角与股骨髁外翻角、胫骨平台内翻角、股胫角的相关关系

[目的]发展一种膝关节术中直接测量股骨后髁角的新方法,并分析股骨后髁角与股骨髁外翻角、胫骨平台内翻角、股胫角的相关性,探讨各角度在膝关节置换术中的意义.[方法]研制股骨后髁角测定仪.对29例(30膝)在本院行人工膝关节置换术的骨关节炎患者,术前测量患膝负重前后位X线片上股骨髁外翻角、胫骨平台内翻角、股胫角,术中用股骨后髁角测定仪测量后髁角;分析股骨后髁角与股骨髁外翻角、胫骨平台内翻角、股胫角的相关关系.[结果]该组股骨后髁角为5.2°±2.6°,股骨髁外翻角为8.6°±2.9°,胫骨平台内翻角为4.1°±4.0°,股胫角为4.1°±7.3°,股骨后髁角和股骨髁外翻角、胫骨平台内翻角之间存在正相关关系,和股胫角尤相关关系.[结论]股骨后髁角测定仪提供了术中测苗股骨后髁角的新方法,为股骨假体旋转对线提供依据;股骨后髁角和股骨髁外翻角、胫骨平台内翻角之间存在正相关关系,术前测量股骨髁外翻角和胫骨平台内翻角,可为股骨假体旋转角度提供参考.     

Enterogenous cysts of the cerebellopontine angle: short review illustrated by two new patients

Summary Intracranial enterogenous cysts are an uncommon entity rarely found in the midline within the posterior cranial fossa. The occurrence of an enterogenous cyst in the cerebellopontine angle is exceptional. We present two new cases of cerebellopontine angle (CPA) enterogenous cysts and review the literature to clarify the diagnosis and the management of these lesions. Eighteen cases of CPA intradural enterogenous cysts have been reported to date, including the two cases presented in this article. All of them were symptomatic and underwent surgical treatment. After surgery, the symptomatic recurrence occurred in 31% of the patients, most of which had partial excision. Considering our patients and the published cases in the literature we suggest that the aim of surgery should be total removal of cyst and its content whenever possible. When partial resection of the cyst is performed, we recommend long-term clinical and neuroradiological follow-up. Correspondence: Paolo Perrini, MD, Neurosurgical Department, Hope Hospital, Salford, Manchester, UK.